scholarly journals ON THE CAPACITY OF SOLAR CELLS UNDER PARTIAL SHADING CONDITIONS

Author(s):  
Mateusz Bartczak

Abstract A photovoltaic system under uniform illumination conditions has only one global maximum power point, but this same panel in the case of partial shading conditions can have more maxima on the power-voltage curve. The motivation of this work are two-fold: to show nonlinear capacitance of solar cell  and to propose a determination technique for partial shading condition. The author shows the results of measurements on a photovoltaic system under different lighting conditions. Shows the effect of capacitance on the shape of the response to excitation in the form of a load. The paper also shows which photovoltaic cell parameters influence the shape of the C-V curve.  

2017 ◽  
Vol 24 (1) ◽  
pp. 193-199
Author(s):  
Mateusz Bartczak

AbstractA single photovoltaic panel under uniform illumination has only one global maximum power point, but the same panel in irregularly illuminated conditions can have more maxima on its power-voltage curve. The irregularly illuminated conditions in most cases are results of partial shading. In the work a single short pulse of load is used to extract information about partial shading. This information can be useful and can help to make some improvements in existing MPPT algorithms. In the paper the intrinsic capacitance of a photovoltaic system is used to retrieve occurrence of partial shading.


Electronics ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 327 ◽  
Author(s):  
Muhammad Afzal Awan ◽  
Tahir Mahmood

Optimal energy extraction under partial shading conditions from a photovoltaic (PV) array is particularly challenging. Conventional techniques fail to achieve the global maximum power point (GMPP) under such conditions, while soft computing techniques have provided better results. The main contribution of this paper is to devise an algorithm to track the GMPP accurately and efficiently. For this purpose, a ten check (TC) algorithm was proposed. The effectiveness of this algorithm was tested with different shading patterns. Results were compared with the top conventional algorithm perturb and observe (P&O) and the best soft computing technique flower pollination algorithm (FPA). It was found that the proposed algorithm outperformed them. Analysis demonstrated that the devised algorithm achieved the GMPP efficiently and accurately as compared to the P&O and the FPA algorithms. Simulations were performed in MATLAB/Simulink.


Author(s):  
Salmi Hassan ◽  
Badri Abdelmajid ◽  
Zegrari Mourad ◽  
Sahel Aicha ◽  
Baghdad Abdenaceur

<p>Maximum power point tracking (MPPT) algorithms are employed in photovoltaic (PV) systems to make full utilization of PV array output power, which have a complex relationship between ambient temperature and solar irradiation. The power-voltage characteristic of PV array operating under partial shading conditions (PSC) exhibits multiple local maximum power points (LMPP). In this paper, an advanced algorithm has been presented to track the global maximum power point (GMPP) of PV. Compared with the Perturb and Observe (P&amp;O) techniques, the algorithm proposed the advantages of determining the location of GMPP whether partial shading is present.</p>


When the photovoltaic sources are subjected to the partial shading (PS) effect, the PV modules are consequently subjected to the different levels of the irradiation. Indeed, when the phenomenon of the partial shading occurs, the Power-Voltage curve of the PV panel presents several points of maximum power. These points are divided between local and global, where the global maximum point presents the superior maximum, and the local maximum points present the inferior maximums compared to the global one. In fact, the classical Maximum Power Point Tracking (MPPT) techniques can not distinguish the global maximum power point, but can track only the first maximum found at the right hand of the Power-Voltage curve. Thus, in some cases, the classical techniques can cause the high drop of power. To solve this issue, this paper proposes a new approach based on the genetic algorithm (GA), because of its ability to optimize the solar panels’ output power production under the PSC. This optimization method is combined with the robust Sliding Mode Controller (SMC). Here, the GA is used in order to locate and generate the reference voltage corresponding to the global maximum power. While the sliding mode controller is used in order to track the reference voltage by acting on the duty cycle of the SEPIC converter. To examine the performance of the proposed method, the comparison with some hybrid controller, which are P&O-SMC, P&O-BSC, INC-BSC and INC-SMC, is performed. The results show the tracking performances of the proposed method, which are the accuracy and rapidity. Moreover, the results illustrates the ability of the proposed hybrid controller to detect the partial shading and to distinguish the Global Maximum Power Point.


2016 ◽  
Vol 2016 ◽  
pp. 1-19 ◽  
Author(s):  
Ru-Min Chao ◽  
Ahmad Nasirudin ◽  
I-Kai Wang ◽  
Po-Lung Chen

This paper identifies the partial shading problem of a PV module using the one-diode model and simulating the characteristics exhibiting multiple-peak power output condition that is similar to a PV array. A modified particle swarm optimization (PSO) algorithm based on the suggested search-agent deployment, retracking condition, and multicore operation is proposed in order to continuously locate the global maximum power point for the PV system. Partial shading simulation results for up to 16 modules in series/parallel formats are presented. A distributed PV system consisting of up to 8 a-silicon thin film PV panels and also having a dedicated DC/DC buck converter on each of the modules is tested. The converter reaches its steady state voltage output in 10 ms. However for MPPT operation, voltage, and current measurement interval is set to 20 ms to avoid unnecessary noise from the entire electric circuit. Based on the simulation and experiment results, each core of the proposed PSO operation should control no more than 4 PV modules in order to have the maximum tracking accuracy and minimum overall tracking time. Tracking for the global maximum power point of a distributed PV system under various partial shading conditions can be done within 1.3 seconds.


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